Freezing of exposed water pipes is well known and is particularly troublesome in those parts of the world where severe freezing is sufficiently infrequent that the housing and plumbing design in construction do not use complete thermal protection of all water pipes since the extra expense is not justified. In such areas, the most common occurrence is the freezing of external water faucets and water pipes to which they are attached, including the extension of the piping into the wall of the house. Rupture during a freeze, followed by melting after the freeze, causes not only damage but, also, a wasteful use of water from the broken valve. Additionally, there is the necessary expense of repair to the valve in the water line associated therewith. A common preventive practice is to manually turn the valves on at least to a bleeding or dripping level prior to the onset of any freezing weather. This works satisfactorily in that the temperature of the household water is sufficient to prevent freezing of the valve and its piping. However, such an operation requires knowledge of an oncoming freezing period and awareness that one must constantly remember to turn the valve. Additionally, if the owners are away from the home when the freezing occurs, this common preventive practice is impossible and the resultant damage occurs.
Numerous devices are known in the prior art. Representative of these various devices are the following patents together with a discussion of the device proposed in the patents.
U.S. Pat. No. 1,134,822 to Lowe illustrates an early system approach to the problem of water pipe freezing wherein a valve is configured to simply respond to a pressure drop resulting from the constriction of water pressure which is created by a self-contained thermal sensing loop within the water pipe as it enters the house.
U.S. Pat. No. 1,200,928 to Egan illustrates an early freeze release valve construction which depends upon an aneroid spring mechanism, and requires manual resetting after a lever has opened the water line to a bleed position.
U.S. Pat. Nos. 1,526,718 and 1,558,276 to Opp and Cartwright respectively, show further water draining devices, and, particularly, integral valving mechanisms. In Opp, the valve member must be opened against the water pressure, so that drained water is insured to freely surround the piston which is then moved by the expansion of the water in a separate chamber. Cartwright shows a container with a valve which will allow release of liquid from the container in response to a freeze. Cooling fluid from the container is allowed to freeze in an exterior region, and then simply lifts up the valve to relieve the pressure. Both Opp and Cartwright are clearly structurally inappropriate for simple mounting upon a male end of a spigot.
U.S. Pat. No. 1,916,038 to Managhan illustrates a valve construction which is dependent upon the fracturing of a glass bottle under freeze conditions. Managhan illustrates a one-shot device wherein replacement of a glass bottle is required each time there has been a freeze.
U.S. Pat. No. 3,320,965 to Morgan illustrates a freeze protection dump valve construction which is configured to respond only to the combined conditions of a lowered line pressure and a subfreezing ambient temperature. Consequently, Morgan significantly requires that the valve close whenever line pressure is greater than, for example, 10 psi, despite any state of contraction for the ambient temperature responsive bellows which he employs.
U.S. Pat. No. 3,369,556 to Allderdice illustrates a freeze device having a single bellows filled with a liquid, such as water. Expansion of the fluid upon a freeze condition will actuate a valve off its seat in a direction against the water pressure within a water line. Importantly, Allderdice requires his device to be mounted vertically and in-line with respect to the household plumbing, with by-pass water passing upwardly, through the device, to an ultimate discharge. It is a permanent part of the household plumbing and not suitable for direct attachment to a water faucet, nor does it operate in conjunction with an existing faucet valve. It stays totally open whenever the ambient temperature is 32.degree. F. or below. Finally, Allderdice's device also requires a lost motion adjustment to ensure actuation, in compensation for its permanency and summer weather.
U.S. Pat. No. 3,380,464 to Arterbury et al is pertinent to an appreciation of the present invention. Arterbury et al illustrates an elongated housing which includes an annular expansion chamber, and, further, a valve member which is hollowed to allow by-pass water to flow through the valve member to an ultimate discharge. Arterbury critically requires that his longitudinally movable valve member be constructed so that the by-pass water will have a heat transfer effect upon the expansion chamber volume. For this purpose, Arterbury requires that a portion of the valve member extend into the household water path in order to ensure that the thermal response of the expansion chamber is dependent upon the temperature of the household water supply. Further, the Arterbury device requires an in-line mounting to the water line.
U.S. Pat. No. 3,397,711 to Strange illustrates a device for releasing water to prevent freezing, wherein contraction of a thermally responsive element opens the drip valve. While Strange illustrates a dump valve mounted upon a downwardly extending spigot, his valving actuator is a series of wafers configured to have a negative coefficient of thermal expansion in the vicinity of 32.degree. F. He critically teaches an external screw adjustment in order to insure valve actuation, and the need for impinging by-pass water directly upon the wafer assembly so as to override a contraction of the wafer due to simple ambient temperatures.
U.S. Pat. No. 3,446,226 to Canterbury is also considered pertinent to an understanding of the present invention, since he teaches an automatic device which is adapted for simple mounting on the male end of a spigot. In Canterbury, the valve actuation is accomplished by a block of material which contracts upon lowered temperatures.
U.S. Pat. No. 3,880,180 to Wismer teaches a water pipe freeze valve which employs a floating piston within an extending housing, whereby expansion of water within the housing raises the piston and snaps open a valve which then opens a separately spaced drain tube. Wismer's construction is, firstly, not adapted to simple mounting on the male end of the spigot and, accordingly, his entire device requires that the piston have a port so that household water from above the piston will be available to fill his expansion fluid volume.
U.S. Pat. No. 4,066,090 to Nakanima et al illustrates a recent patent relating to a water cock having an integrally mounted non-freezing valve. This device operates on the principle of bringing relatively warmer line water up to the valve. This patent also begins with an ambient, local temperature, but then also functions in response to the household water temperature reaching the valve.
U.S. Pat. No. 4,205,698 to Hucks involves the use of a fluid having a negative coefficient of expansion with reduced temperature, with the volumetric change being a gradual change related to temperature rather than being activated at a given, desirable temperature. Also, this valve is dependent upon a spring and several seals. If the seal leaks between the chamber where water exists and the chamber containing the spring, water will flow into the intermediate space, freeze, and make the entire valve inoperable. This valve further requires that bleed water be diverted from the valve in order not to interfere with sensing of true ambient temperature.
An object of the present invention is to provide a device which utilizes the freezing condition as it occurs to self actuate water flow and to prevent line freeze up.
A further object of the invention is to provide a self-actuated water flow valve having substantially few required movable parts and with no necessity of using supplemental springs, packing seals or glands.
Another object of the invention is to provide a self-actuating water valve which requires no need for thermal calibration of mechanical devices.
Yet another object of this invention is to provide a self-actuating water valve which requires no need for resetting the valve after actuation thereof.
A still further object of the invention is to provide a self-actuating drip valve which requires no special activating fluids relative to any sliding surfaces which may be subject to freezing or the like.
Yet a further object of this invention is to provide a device which easily attaches to existing water faucets so that there is no need to permanently install the device in the piping system.
These and other objects of the invention will become apparent from the following description when taken in conjunction with the drawings.